1. Field
Exemplary embodiments relate to an ultrasonic probe having a backing layer which varies acoustic impedance and a manufacturing method thereof.
2. Description of the Related Art
An ultrasonic diagnosis apparatus irradiates an ultrasonic signal toward a target region of the interior of a body of an object from the surface of the body of the object, and acquires an image regarding soft tissue tomography or a blood stream through a non-invasive technique using information of a reflected ultrasonic signal (an ultrasonic echo signal).
The ultrasonic diagnosis apparatus is small and inexpensive, executes display in real time and has a high safety level without radiation exposure, as compared to other image diagnosis apparatuses, such as an X-ray diagnosis apparatus, an X-ray computerized tomography (CT) scanner, a magnetic resonance imager (MRI) and a nuclear medicine diagnosis apparatus, and is thus widely used for heart diagnosis, celiac diagnosis, urinary diagnosis and obstetrical diagnosis.
Particularly, the ultrasonic diagnosis apparatus includes an ultrasonic probe which transmits an ultrasonic signal to an object and which receives an ultrasonic echo signal reflected by the object to acquire an ultrasonic image of the object.
The ultrasonic probe includes a piezoelectric layer in which a piezoelectric material vibrates to execute conversion between an electrical signal and an acoustic signal, a matching layer which reduces an acoustic impedance difference between the piezoelectric layer and the object so as to maximally transmit ultrasonic waves generated from the piezoelectric layer to the object, a lens which concentrates ultrasonic waves proceeding in the forward direction of the piezoelectric layer on a specific point, and a backing layer which prevents ultrasonic waves from proceeding in the backward direction of the piezoelectric layer to prevent image distortion.
The lens has a convex structure in the outward direction so as to concentrate ultrasonic waves, and such a structure attenuates the intensity of ultrasonic waves. Particularly, the intensity of ultrasonic waves at the central region of the lens requiring a high output is more reduced than the intensity of ultrasonic waves at the side regions of the lens.